Mobile station apparatus, base station apparatus, radio communication system, radio communication method, and integrated circuit

ABSTRACT

In a radio communication system using OCC for DMRS, a base station apparatus correctly receives PUSCH. If a first mode is set in which a demodulation reference signal of a physical uplink shared channel is multiplied by an orthogonal code determined in advance or if a temporary C-RNTI was used for a transmission of downlink control information, the demodulation reference signal of the physical uplink shared channel is multiplied by the orthogonal code determined in advance, and if a second mode is set in which the demodulation reference signal of the physical uplink shared channel is multiplied by an orthogonal code determined on the basis of cyclic shift information in the downlink control information and moreover, if an RNTI other than the temporary C-RNTI was used for the transmission of the downlink control information, the demodulation reference signal of the physical uplink shared channel is multiplied by the orthogonal code determined on the basis of the cyclic shift information in the downlink control information.

TECHNICAL FIELD

The present invention relates to a radio communication system, a basestation apparatus, a mobile station apparatus, a radio communicationmethod, and an integrated circuit.

BACKGROUND ART

Evolution of a radio access method and a radio network of a cellularmobile communication (hereinafter referred to as “Long Term Evolution(LTE)” or “Evolved Universal Terrestrial Radio Access (EUTRA)”) is beingexamined in the 3rd Generation Partnership Project (3GPP). In the LTE,as a communication system for radio communication (downlink) from a basestation apparatus to a mobile station apparatus, the OrthogonalFrequency Division Multiplexing (OFDM) system which is amultiple-carrier transmission is used. In addition, as a communicationsystem of the radio communication (uplink) from the mobile stationapparatus to the base station apparatus, the Single-Carrier FrequencyDivision Multiple Access (SC-FDMA) system which is a single-carriertransmission is used.

In the LTE, the base station apparatus instructs the mobile stationapparatus to perform initial transmission or retransmission of PUSCH(Physical Uplink Shared Channel) which is a channel for uplink data (orreferred to as “uplink shared channel: UL-SCH”) transmission by usingDownlink Control Information (DCI) transmitted via PDCCH (PhysicalDownlink Control Channel). In the LTE, the mobile station apparatustransmits PUSCH by using one transmission antenna port.

In the LTE-A, use of SU (single user)-MIMO (Multiple Input MultipleOutput) for the PUSCH is being examined in order to improve spectrumefficiency of the uplink. By using the SU-MIMO, the mobile stationapparatus can spatially multiplex a plurality of pieces of uplink datain one PUSCH and transmit it by using a plurality of antenna ports. Inthe LTE, MU (multi user)-MIMO is used which is a technology to improvethe spectrum efficiency in which a plurality of the mobile stationapparatuses transmits data at the same time and the same frequency andthe base station apparatus, when receiving the data, separates data ofone or more sequences transmitted by each of the mobile stationapparatuses, but in the LTE-A, expansion of the functions of MU-MIMO isbeing examined.

In the LTE, a cyclic shift has been introduced to a reference signal(Demodulation Reference Signal: DMRS) used for channel estimation andtransmitted together with the PUSCH in order to reduce interference.Non-Patent Document 1 describes introduction of OCC (Orthogonal CoverCode) into the DMRS in order to further reduce interference of the DMRSduring SU-MIMO and MU-MIMO. Moreover, Non-Patent Document 1 describesthat information relating to the cyclic shift used for the DMRS andincluded in the downlink control information for the PUSCH is associatedwith the OCC used for the DMRS.

PRIOR ART DOCUMENT Non-Patent Document

-   Non-patent Document 1: “OCC and CS for UL DMRS in SU/MU-MIMO”, 3GPP    TSG RAN WG1 Meeting #60, R1-101267, Feb. 22 to 26, 2010

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in the prior-art technology, if the base station apparatus canno longer recognize whether the mobile station apparatus operates as theLTE and the OCC is not used for the DMRS or the mobile station apparatusoperates as the LTE-A and the OCC is used for the DMRS, the base stationapparatus cannot correctly perform the channel estimation from the DMRStransmitted by the mobile station apparatus, and a problem occurs thatthe PUSCH cannot be received.

The present invention was made in view of the above problem and has anobject to provide a mobile station apparatus, a base station apparatus,a radio communication system, a radio communication method, and anintegrated circuit in which the base station apparatus can correctlyreceive the PUSCH in a radio communication system using the OCC for theDMRS.

Means for Solving the Problems

(1) In order to achieve the above-described object, an embodiment of thepresent invention takes the following measures. That is, a mobilestation apparatus of an embodiment of the present invention is a mobilestation apparatus that communicates with a base station apparatus,wherein: when the mobile station apparatus decodes downlink controlinformation in a predetermined format used for scheduling of a physicaluplink shared channel, if a first mode is set in which a demodulationreference signal of the physical uplink shared channel is multiplied byan orthogonal code determined in advance or if a temporary C-RNTI wasused for a transmission of the downlink control information, the mobilestation apparatus decodes multiplies the demodulation reference signalof the physical uplink shared channel scheduled by the downlink controlinformation by the orthogonal code determined in advance, and when themobile station apparatus decodes the downlink control information in thepredetermined format used for scheduling of the physical uplink sharedchannel, if a second mode is set in which the demodulation referencesignal of the physical uplink shared channel is multiplied by anorthogonal code determined on the basis of cyclic shift information inthe downlink control information and moreover, if an RNTI other than thetemporary C-RNTI was used for the transmission of the downlink controlinformation, the mobile station apparatus decodes multiplies thedemodulation reference signal of the physical uplink shared channelscheduled by the downlink control information by the orthogonal codedetermined on the basis of the cyclic shift information in the downlinkcontrol information.

(2) Moreover, in the mobile station apparatus of an embodiment of thepresent invention, the RNTI other than the temporary C-RNTI is a C-RNTIor an SPS C-RNTI.

(3) In addition, in the mobile station apparatus of an embodiment of thepresent invention, the downlink control information in the predeterminedformat is information for scheduling the physical uplink shared channeltransmitted on a single antenna port.

(4) Moreover, in the mobile station apparatus of an embodiment of thepresent invention, the first mode or the second mode is set inaccordance with an RRC signal received from the base station apparatus.

(5) Furthermore, in the mobile station apparatus of an embodiment of thepresent invention, the first mode is set until the RRC signal isreceived from the base station apparatus.

(6) Moreover, in the mobile station apparatus of an embodiment of thepresent invention, the temporary C-RNTI is included in a random accessresponse including a random access preamble identifier transmitted bythe mobile station apparatus to the base station apparatus.

(7) In addition, in the mobile station apparatus of an embodiment of thepresent invention, the downlink control information including the RNTIother than the temporary C-RNTI is decoded in a common search spaceand/or a mobile station apparatus specific search space and the downlinkcontrol information including the temporary C-RNTI is decoded in thecommon search space.

(8) Moreover, in the mobile station apparatus of an embodiment of thepresent invention, the common search space is a space constituted by apredetermined control channel element; and the mobile station apparatusspecific search space is a space constituted by a control channelelement determined on the basis of a C-RNTI which is the RNTI other thanthe temporary C-RNTI.

(9) Furthermore, in the mobile station apparatus of an embodiment of thepresent invention, when the mobile station apparatus decodes thedownlink control information in a format used for scheduling of thephysical uplink shared channel other than the predetermined format, themobile station apparatus multiplies the demodulation reference signal ofthe physical uplink shared channel scheduled by the downlink controlinformation in the format other than the predetermined format by theorthogonal code determined on the basis of the cyclic shift informationin the downlink control information in the format other than thepredetermined format.

(10) Moreover, in the mobile station apparatus of an embodiment of thepresent invention, the downlink control information in the format otherthan the predetermined format is information for scheduling the physicaluplink shared channel transmitted on a plurality of the antenna ports.

(11) In addition, the mobile station apparatus of an embodiment of thepresent invention is a mobile station apparatus that communicates with abase station apparatus, wherein: the mobile station apparatus, on thebasis of an RNTI used for the transmission of downlink controlinformation in a predetermined format used for scheduling of a physicaluplink shared channel, multiplies a demodulation reference signal of thephysical uplink shared channel scheduled by the downlink controlinformation by an orthogonal code determined in advance, or multipliesthe demodulation reference signal of the physical uplink shared channelscheduled by the downlink control information by an orthogonal codedetermined on the basis of cyclic shift information in the downlinkcontrol information.

(12) Moreover, the mobile station apparatus of an embodiment of thepresent invention is a mobile station apparatus that communicates with abase station apparatus, wherein: the mobile station apparatus sets, inaccordance with an RRC signal received from the base station apparatus,a first mode in which the mobile station apparatus, when decodingdownlink control information in a format used for scheduling of aphysical uplink shared channel transmitted on a single antenna port,multiplies a demodulation reference signal of the physical uplink sharedchannel scheduled by the downlink control information by an orthogonalcode determined in advance, or a second mode in which the mobile stationapparatus, when decoding the downlink control information in the formatused for scheduling of the physical uplink shared channel transmitted ona single antenna port, multiplies the demodulation reference signal ofthe physical uplink shared channel scheduled by the downlink controlinformation by an orthogonal code determined on the basis of cyclicshift information in the downlink control information.

(13) Furthermore, the base station apparatus of an embodiment of thepresent invention is a base station apparatus that communicates with amobile station apparatus, wherein: when the base station apparatustransmits downlink control information in a predetermined format usedfor scheduling of a physical uplink shared channel to the mobile stationapparatus, if a first mode is set, to said mobile station apparatus, inwhich the mobile station apparatus multiplies a demodulation referencesignal of the physical uplink shared channel scheduled by the downlinkcontrol information in the predetermined format by an orthogonal codedetermined in advance or if a temporary C-RNTI was used for the atransmission of the downlink control information, the base stationapparatus receives, from the mobile station apparatus, the demodulationreference signal of the physical uplink shared channel multiplied, bythe mobile station apparatus, by the orthogonal code determined inadvance; and when the base station apparatus transmits the downlinkcontrol information in the predetermined format used for the schedulingof the physical uplink shared channel to the mobile station apparatus,if a second mode is set, to said mobile station apparatus, in which themobile station apparatus multiplies the demodulation reference signal ofthe physical uplink shared channel scheduled by the downlink controlinformation in the predetermined format by an orthogonal code determinedon the basis of cyclic shift information in the downlink controlinformation, and if an RNTI other than the temporary C-RNTI was used forthe transmission of the downlink control information, the base stationapparatus receives, from the mobile station apparatus, the demodulationreference signal of the physical uplink shared channel multiplied by theorthogonal code determined by the mobile station apparatus on the basisof the cyclic shift information in the downlink control information.

(14) Moreover, in the base station apparatus of an embodiment of thepresent invention, the RNTI other than the temporary C-RNTI is a C-RNTIor an SPS C-RNTI.

(15) In addition, in the base station apparatus of an embodiment of thepresent invention, the downlink control information in the predeterminedformat is information for scheduling the physical uplink shared channeltransmitted by using a single antenna port.

(16) Moreover, in the base station apparatus of an embodiment of thepresent invention, an RRC signal indicating the first mode or the secondmode is transmitted to the mobile station apparatus.

(17) Furthermore, in the base station apparatus of an embodiment of thepresent invention, the mobile station apparatus is considered to set thefirst mode until the RRC signal is transmitted to the mobile stationapparatus.

(18) Moreover, in the base station apparatus of an embodiment of thepresent invention, the temporary C-RNTI is included in a random accessresponse including a random access preamble identifier transmitted bythe mobile station apparatus to the base station apparatus.

(19) In addition, in the base station apparatus of an embodiment of thepresent invention, the downlink control information including the RNTIother than the temporary C-RNTI is transmitted in a common search spaceand/or a mobile station apparatus specific search space and the downlinkcontrol information including the temporary C-RNTI is transmitted in thecommon search space.

(20) Moreover, in the base station apparatus of an embodiment of thepresent invention, the common search space is a space constituted by apredetermined control channel element, and the mobile station apparatusspecific search space is a space constituted by a control channelelement determined on the basis of a C-RNTI which is the RNTI other thanthe temporary C-RNTI.

(21) Furthermore, in the base station apparatus of an embodiment of thepresent invention, when the base station apparatus transmits thedownlink control information in a format used for scheduling of thephysical uplink shared channel other than the predetermined format tothe mobile station apparatus, the base station apparatus receives thedemodulation reference signal of the physical uplink shared channelwhich is multiplied by the orthogonal code determined by the mobilestation apparatus on the basis of the cyclic shift information in thedownlink control information in the format other than the predeterminedformat, and the physical uplink shared channel is scheduled by thedownlink control information in the format other than the predeterminedformat.

(22) Moreover, in the base station apparatus of an embodiment of thepresent invention, the downlink control information in the format otherthan the predetermined format is information for scheduling the physicaluplink shared channel transmitted on a plurality of the antenna ports.

(23) In addition, the base station apparatus of an embodiment of thepresent invention is a base station apparatus that communicates with amobile station apparatus, wherein the base station apparatus, inaccordance with an RNTI used for the transmission of downlink controlinformation used for scheduling of a physical uplink shared channel,receives a demodulation reference signal of the physical uplink sharedchannel scheduled by the downlink control information, which ismultiplied, by the mobile station apparatus, by an orthogonal codedetermined in advance, or receives the demodulation reference signal ofthe physical uplink shared channel scheduled by the downlink controlinformation, which is multiplied by an orthogonal code determined by themobile station apparatus on the basis of cyclic shift information in thedownlink control information.

(24) Moreover, the base station apparatus of an embodiment of thepresent invention is a base station apparatus that communicates with amobile station apparatus, wherein the base station apparatus, inaccordance with a mode indicated by an RRC signal transmitted to themobile station apparatus, receives, when transmitting downlink controlinformation in a format used for scheduling of a physical uplink sharedchannel transmitted on a single antenna port to said mobile stationapparatus, a demodulation reference signal of the physical uplink sharedchannel which is scheduled by said downlink control information, and thedemodulation reference signal is multiplied, by said mobile stationapparatus, by an orthogonal code determined in advance, or receives,when transmitting the downlink control information in the format usedfor scheduling of the physical uplink shared channel transmitted byusing a single antenna port to said mobile station apparatus, thedemodulation reference signal of the physical uplink shared channelwhich is scheduled by said downlink control information, and thedemodulation reference signal is multiplied by an orthogonal codedetermined on the basis of cyclic shift information in said downlinkcontrol information by said mobile station apparatus.

(25) Furthermore, the radio communication system of an embodiment of thepresent invention is a radio communication system in which a mobilestation apparatus and abase station apparatus communicate with eachother, wherein the mobile station apparatus, when decoding downlinkcontrol information in a predetermined format used for scheduling of aphysical uplink shared channel, if a first mode is set in which ademodulation reference signal of the physical uplink shared channelscheduled by the downlink control information in the predeterminedformat is multiplied by an orthogonal code determined in advance, or ifa temporary C-RNTI was used for a transmission of the downlink controlinformation, multiplies the demodulation reference signal of thephysical uplink shared channel by the orthogonal code determined inadvance; and when decoding the downlink control information in apredetermined format used for scheduling of the physical uplink sharedchannel, if a second mode is set in which the demodulation referencesignal of the physical uplink shared channel scheduled by the downlinkcontrol information in the predetermined format is multiplied by anorthogonal code determined on the basis of cyclic shift information inthe downlink control information, and moreover, if an RNTI other thanthe temporary C-RNTI was used for the transmission of the downlinkcontrol information, multiplies the demodulation reference signal of thephysical uplink shared channel by the orthogonal code determined on thebasis of the cyclic shift information in the downlink controlinformation, and transmits the demodulation reference signal of thephysical uplink shared channel to the base station apparatus; andwherein the base station apparatus, when transmitting the downlinkcontrol information in a predetermined format used for scheduling of thephysical uplink shared channel to the mobile station apparatus, if afirst mode is set, to said mobile station apparatus, in which the mobilestation apparatus multiplies the demodulation reference signal of thephysical uplink shared channel scheduled by the downlink controlinformation in the predetermined format by the orthogonal codedetermined in advance or if the temporary C-RNTI was used for thetransmission of the downlink control information, receives, from themobile station apparatus, the demodulation reference signal of thephysical uplink shared channel multiplied by the orthogonal codedetermined in advance by the mobile station apparatus; and whentransmitting the downlink control information in a predetermined formatused for scheduling of the physical uplink shared channel to the mobilestation apparatus, if a second mode is set, to said mobile stationapparatus, in which the mobile station apparatus multiplies thedemodulation reference signal of the physical uplink shared channelscheduled by the downlink control information in the predeterminedformat by the orthogonal code determined on the basis of the cyclicshift information in the downlink control information, and if the RNTIother than the temporary C-RNTI was used for the transmission of thedownlink control information, receives, from the mobile stationapparatus, the demodulation reference signal of the physical uplinkshared channel multiplied by the orthogonal code determined on the basisof the cyclic shift information in the downlink control information bythe mobile station apparatus.

(26) Moreover, the radio communication method of an embodiment of thepresent invention is a radio communication method used in a mobilestation apparatus that communicates with a base station apparatus, themethod comprising the steps of: when decoding downlink controlinformation in a predetermined format used for scheduling of a physicaluplink shared channel, if a first mode is set in which a demodulationreference signal of the physical uplink shared channel is multiplied byan orthogonal code determined in advance or if a temporary C-RNTI wasused for a transmission of the downlink control information, multiplyingthe demodulation reference signal of the physical uplink shared channelscheduled by the downlink control information by the orthogonal codedetermined in advance, and when decoding the downlink controlinformation in the predetermined format used for scheduling of thephysical uplink shared channel, if a second mode is set in which thedemodulation reference signal of the physical uplink shared channel ismultiplied by an orthogonal code determined on the basis of cyclic shiftinformation in the downlink control information and moreover, if an RNTIother than the temporary C-RNTI was used for the transmission of thedownlink control information, multiplying the demodulation referencesignal of the physical uplink shared channel scheduled by the downlinkcontrol information by the orthogonal code determined on the basis ofthe cyclic shift information in the downlink control information.

(27) In addition, the radio communication method of an embodiment of thepresent invention is a radio communication method used in a base stationapparatus communicating with a mobile station apparatus, the methodcontrolling processing of the base station apparatus of: whentransmitting downlink control information in a predetermined format usedfor scheduling of a physical uplink shared channel to the mobile stationapparatus, if a first mode is set, to said mobile station apparatus, inwhich the mobile station apparatus multiplies a demodulation referencesignal of the physical uplink shared channel scheduled by the downlinkcontrol information in the predetermined format by an orthogonal codedetermined in advance or if a temporary C-RNTI was used for atransmission of the downlink control information, receiving thedemodulation reference signal of the physical uplink shared channelmultiplied, by the mobile station apparatus, by the orthogonal codedetermined in advance; and when transmitting the downlink controlinformation in the predetermined format used for the scheduling of thephysical uplink shared channel to the mobile station apparatus, if asecond mode is set, to said mobile station apparatus, in which themobile station apparatus multiplies the demodulation reference signal ofthe physical uplink shared channel scheduled by the downlink controlinformation in the predetermined format by an orthogonal code determinedon the basis of cyclic shift information in the downlink controlinformation, and if an RNTI other than the temporary C-RNTI was used forthe transmission of the downlink control information, receiving thedemodulation reference signal of the physical uplink shared channelmultiplied by the orthogonal code determined by the mobile stationapparatus on the basis of the cyclic shift information in the downlinkcontrol information.

(28) Moreover, the integrated circuit of an embodiment of the presentinvention is an integrated circuit used in a mobile station apparatusthat communicates with a base station apparatus, wherein the integratedcircuit, when decoding downlink control information in a predeterminedformat used for scheduling of a physical uplink shared channel, if afirst mode is set in which a demodulation reference signal of thephysical uplink shared channel is multiplied by an orthogonal codedetermined in advance or if a temporary C-RNTI was used for atransmission of the downlink control information, multiplies thedemodulation reference signal of the physical uplink shared channelscheduled by the downlink control information by the orthogonal codedetermined in advance, and when decoding the downlink controlinformation in the predetermined format used for scheduling of thephysical uplink shared channel, if a second mode is set in which thedemodulation reference signal of the physical uplink shared channel ismultiplied by an orthogonal code determined on the basis of cyclic shiftinformation in the downlink control information and moreover, if an RNTIother than the temporary C-RNTI was used for the transmission of thedownlink control information, multiplies the demodulation referencesignal of the physical uplink shared channel scheduled by the downlinkcontrol information by the orthogonal code determined on the basis ofthe cyclic shift information in the downlink control information.

(29) Furthermore, the integrated circuit of an embodiment of the presentinvention is an integrated circuit used in a base station apparatus thatcommunicates with a mobile station apparatus, wherein the integratedcircuit controls processing of the base station apparatus of: whentransmitting downlink control information in a predetermined format usedfor scheduling of a physical uplink shared channel to the mobile stationapparatus, if a first mode is set, to said mobile station apparatus, inwhich the mobile station apparatus multiplies a demodulation referencesignal of the physical uplink shared channel scheduled by the downlinkcontrol information in the predetermined format by an orthogonal codedetermined in advance or if a temporary C-RNTI was used for atransmission of the downlink control information, receiving thedemodulation reference signal of the physical uplink shared channelmultiplied, by the mobile station apparatus, by the orthogonal codedetermined in advance; and when transmitting the downlink controlinformation in the predetermined format used for the scheduling of thephysical uplink shared channel to the mobile station apparatus, if asecond mode is set, to said mobile station apparatus, in which themobile station apparatus multiplies the demodulation reference signal ofthe physical uplink shared channel scheduled by the downlink controlinformation in the predetermined format by an orthogonal code determinedon the basis of cyclic shift information in the downlink controlinformation, and if an RNTI other than the temporary C-RNTI was used forthe transmission of the downlink control information, receiving thedemodulation reference signal of the physical uplink shared channelmultiplied by the orthogonal code determined by the mobile stationapparatus on the basis of the cyclic shift information in the downlinkcontrol information.

Effect of the Invention

According to the present invention, in the radio communication systemusing OCC for DMRS, the base station apparatus can correctly receive thePUSCH.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram illustrating a configuration of amobile station apparatus 1 of an embodiment of the present invention.

FIG. 2 is a schematic block diagram illustrating a configuration of abase station apparatus 3 of an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining a generating method of DMRSin an embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating an example of a configurationof a search space in which PDCCH is arranged in an embodiment of thepresent invention.

FIG. 5 is a diagram illustrating a relationship between an uplink grantand an OCC applied to DMRS in an embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship between cyclic shiftinformation and a cyclic shift applied to the DMRS in an embodiment ofthe present invention.

FIG. 7 is a diagram illustrating a relationship among the cyclic shiftinformation, the cyclic shift applied to the DMRS and the OCC in anembodiment of the present invention.

FIG. 8 is a flowchart illustrating an example of an operation of themobile station apparatus 1 of an embodiment of the present invention.

FIG. 9 is a flowchart illustrating an example of an operation of thebase station apparatus 3 of an embodiment of the present invention.

FIG. 10 is a diagram illustrating a relationship between an uplink grantand the OCC applied to the DMRS in a second embodiment of the presentinvention.

FIG. 11 is a conceptual diagram of a radio communication systemaccording to a first embodiment of the present invention.

FIG. 12 is a schematic diagram illustrating an example of aconfiguration of a radio frame of a downlink in an embodiment of thepresent invention.

FIG. 13 is a schematic diagram illustrating an example of aconfiguration of a radio frame of an uplink in an embodiment of thepresent invention.

BEST MODES FOR CARRYING OUT THE INVENTION First Embodiment

A first embodiment of the present invention will be described below indetail by referring to the attached drawings.

First, a physical channel of the present invention will be described.

FIG. 11 is a conceptual diagram of a radio communication systemaccording to the first embodiment of the present invention. In FIG. 11,the radio communication system includes mobile station apparatuses 1A to1C and a base station apparatus 3. FIG. 11 illustrates assignment of aSynchronization Signal (SS), a Downlink Reference Signal (DL RS), aPhysical Broadcast Channel (PBCH), a Physical Downlink Control Channel(PDCCH), a Physical Downlink Shared Channel (PDSCH), a PhysicalMulticast Channel (PMCH), a Physical Control Format Indicator Channel(PCFICH), and a Physical Hybrid ARQ Indicator Channel (PHICH) in theradio communication (downlink) from the base station apparatus 3 to themobile station apparatuses 1A to 1C.

Moreover, FIG. 11 illustrates assignment of an Uplink Reference Signal(UL RS), a Physical Uplink Control Channel (PUCCH), a Physical UplinkShared Channel (PUSCH), and a Physical Random Access Channel (PRACH) inthe radio communication (uplink) from the mobile station apparatuses 1Ato 1C to the base station apparatus 3. Hereinafter, the mobile stationapparatuses 1A to 1C will be referred to as a mobile station apparatus1.

The synchronization signal is a signal used for the mobile stationapparatus 1 to synchronize in terms of a frequency domain and a timedomain of the downlink. The downlink reference signal is a signal usedfor the mobile station apparatus 1 to synchronize in terms of thefrequency domain and the time domain of the downlink, used for themobile station apparatus 1 to measure reception quality of the downlinkor used for the mobile station apparatus 1 to perform channelcompensation of PDSCH and PDCCH. The PBCH is a physical channel used forbroadcasting a control parameter (system information) (BroadcastChannel: BCH) used in common by the mobile station apparatus 1. The PBCHis transmitted at 40-ms interval. The timing at the 40-ms interval isblind-detected in the mobile station apparatus 1.

The PDCCH is a physical channel used for transmitting Downlink ControlInformation (DCI)) such as a downlink assignment (or also referred to asa downlink grant) and an uplink grant. The downlink assignment includesinformation relating to a modulation scheme and a coding rate of thePDSCH (Modulation and Coding Scheme: MCS), information indicatingassignment of radio resources of the PDSCH and the like. The uplinkgrant includes information relating to the modulation scheme and thecoding rate of the PUSCH, information indicating assignment of the radioresources of the PUSCH and the like.

A plurality of formats is used for the downlink control information. Theformat for the downlink control information is referred to as a DCIformat. For example, for the DCI format for the uplink grant, a DCIformat 0 used when the mobile station apparatus 1 transmits the PUSCH byusing one transmission antenna port, a DCI format 0A used when themobile station apparatus 1 transmits a plurality of pieces of uplinkdata by using MIMO SM (Multiple Input Multiple Output SpatialMultiplexing) for the PUSCH and the like are prepared. The mobilestation apparatus 1 monitors the DCI format 0 and the DCI format 0A forthe PDCCH at the same time, and if the DCI format 0 is detected, thePUSCH is transmitted by using one transmission antenna port, while ifthe DCI format 0A is detected, the PUSCH is transmitted by using aplurality of transmission antenna ports (MIMO SM).

The MIMO SM is a technology in which a plurality of signals ismultiplexed and transmitted/received with respect to a channel of aplurality of spatial dimensions realized by a plurality of transmissionantenna ports and a plurality of reception antenna ports. Here, theantenna port refers to a logical antenna used for signal processing. Oneantenna port may be composed of one physical antenna or may be composedof a plurality of physical antennas. On the transmission side using theMIMO SM, processing for forming a spatial channel appropriate for theplurality of signals (referred to as precoding) is executed, and aplurality of signals subjected to the precoding processing istransmitted by using the plurality of transmission antennas. On thereception side using the MIMO SM, processing for appropriatelyseparating the signals multiplexed in the channel of spatial dimensionsis performed on a plurality of signals received by using the pluralityof reception antennas.

For example, the DCI format 0A includes information indicatingassignment of the radio resources for the PUSCH (Resource blockassignment), a TPC (Transmission Power Control) command used fortransmit power control of the PUSCH, information used for determining acyclic shift used for an uplink reference signal time-multiplexed withthe PUSCH (hereinafter referred to as cyclic shift information) (Cyclicshift for demodulation reference signal), information for indicating thenumber of space-multiplexed sequences and precoding performed on thesesequences (precoding information), information relating to themodulation scheme, the coding method, and redundancy version (Modulationand Coding Scheme and Redundancy version: MCS&RV), and informationindicating initial transmission or retransmission of the uplink data(New Data Indicator: NDI). The redundancy version is informationindicating which part, in bit sequences in which the uplink data isencoded, is to be transmitted by the mobile station apparatus 1 in thePUSCH.

The MCS&RV and the NDI included in the DCI format 0A are prepared foreach of the plurality of pieces of uplink data controlled by the DCIformat 0A. That is, the base station apparatus 3 can set the transportblock size, the modulation scheme, and the coding rate for each uplinkdata transmitted on the same PUSCH and can indicate initial transmissionor retransmission to the mobile station apparatus 1 for each uplink databy using the DCI format 0A.

The encoding method of the downlink control information will bedescribed. First, the base station apparatus 3 attaches, to the downlinkcontrol information, a sequence obtained by scrambling a CyclicRedundancy Check (CRC) code generated on the basis of the downlinkcontrol information with a Radio Network Temporary Identifier (RNTI).The mobile station apparatus 1 changes interpretation of the downlinkcontrol information on the basis of with which RNTI the CRC code isscrambled.

For example, the mobile station apparatus 1, when the CRC code isscrambled with a C-RNTI (Cell-Radio Network Temporary Identity) assignedby the base station apparatus 3 to its own apparatus, determines thatthe downlink control information indicates a radio resource addressed toits own apparatus, while when the CRC code is scrambled with an SPS(Semi Persistent Scheduling) C-RNTI assigned by the base stationapparatus 3 to its own apparatus, the mobile station apparatus 1determines that the downlink control information indicates permanent(periodic) assignment of the radio resource to its own apparatus orrelease of the permanent radio resource or retransmission for the PUSCHtransmitted by the permanent radio resource.

The mobile station apparatus 1, when the CRC code is scrambled with a T(Temporary) C-RNTI assigned to a random access preamble transmitted byits own apparatus in a random access message 2, determines that thedownlink control information indicates the radio resource forretransmission of a random access message 3 transmitted by its ownapparatus. The details of the random access will be described later.

Hereinafter, the fact that the CRC code scrambled with the RNTI isattached to the downlink control information is expressed simply as thatthe RNTI is included in the downlink control information or the RNTI isincluded in the PDCCH.

The mobile station apparatus 1 determines that the PDCCH is successfullyobtained when the PDCCH is decode-processed, a sequence corresponding tothe CRC code scrambled with the RNTI is descrambled with the RNTI storedin its own apparatus, and no error is detected on the basis of thedescrambled CRC code. This processing is referred to as blind decoding.

The PDSCH is a physical channel used for transmitting paging information(Paging Channel: PCH) or system information not broadcasted in PBCH,that is, information other than BCH and downlink data (Downlink SharedChannel: DL-SCH). The PMCH is a physical channel used for transmittinginformation (Multicast Channel: MCH) relating to MBMS (MultimediaBroadcast and Multicast Service). The PCFICH is a physical channel usedfor transmitting information indicating a region in which the PDCCH isarranged. The PHICH is a physical channel used for transmitting the HARQindicator indicating success/failure of decoding of the uplink datareceived by the base station apparatus 3.

When the base station apparatus 3 has succeeded in decoding all theuplink data included in the PUSCH, the HARQ indicator indicates ACK(ACKnowledgment), while when the base station apparatus 3 has failed indecoding at least one piece of uplink data included in the PUSCH, theHARQ indicator indicates NACK (Negative ACKnowledgment). It may be soconfigured that a plurality of the HARQ indicators indicatingsuccess/failure of decoding for each of the plurality of pieces ofuplink data included in the same PUSCH is transmitted in a plurality ofthe PHICHs.

The uplink reference signal is a signal used for the base stationapparatus 3 to synchronize with the time domain of the uplink, used forthe base station apparatus 3 to measure reception quality of the uplinkor used for the base station apparatus 3 to perform channel compensationof the PUSCH or PUCCH. The uplink reference signal is subjected to codespread using a CAZAC (Constant Amplitude and Zero Auto-Correlation)sequence in the radio resource divided assuming SC-FDMA.

The CAZAC sequence is a sequence which has constant amplitude in a timedomain and a frequency domain and is excellent in auto-correlationcharacteristics. Since it has constant amplitude in the time domain,PAPR (Peak to Average Power Ratio) can be suppressed low. Cyclic delayis applied to the DMRS in the time domain. This cyclic delay in the timedomain is referred to as a cyclic shift. The cyclic shift corresponds tophase rotation of the CAZAC sequence by the unit of a subcarrier in thefrequency domain.

The uplink reference signal includes a DMRS (Demodulation ReferenceSignal) which is time-multiplexed with the PUSCH or the PUCCH andtransmitted and which is used for channel compensation for the PUSCH andPUCCH, and an SRS (Sounding Reference Signal) which is transmittedindependently from the PUSCH and PUCCH and which is used for the basestation apparatus 3 to estimate channel state of the uplink. For theDMRS, not only the cyclic shift but also an OCC (Orthogonal Cover Code)is used. The OCC is a sequence (spread signal) in which the CAZACsequence in the frequency domain is subjected to code spread by the unitof SC-FDMA symbol in the time domain. The SC-FDMA symbol in the timedomain may be subjected to code-spread with the OCC after the SC-FDMAsymbol is generated.

The OCC used for the DMRS is determined by using the cyclic shiftinformation included in the uplink grant. A shift amount of the cyclicshift used for the DMRS is determined from the cyclic shift informationincluded in the uplink grant, a parameter specific to the base stationapparatus broadcasted from the base station apparatus, and a randomnumber determined by using a Physical Cell ID assigned to a cell managedby the base station apparatus from a network and the like as an input.

The PUCCH is a physical channel used for transmitting Uplink ControlInformation (UCI) which is information used for control of communicationsuch as Channel Quality Information indicating a channel quality of adownlink, a Scheduling Request (SR) indicating a request for assignmentof a radio resource of the uplink, ACK/NACK indicating success/failureof decoding of the downlink data received by the mobile stationapparatus 1 and the like.

The PUSCH is a physical channel used for transmitting the uplink dataand uplink control information. The PRACH is a physical channel used fortransmitting a random access preamble. The PRACH has the most importantobject of synchronizing the mobile station apparatus 1 with the basestation apparatus 3 in the time domain and in addition is also used foran initial access, handover, a request for reconnection, and a requestfor assignment of a radio resource of the uplink.

The random access of the present invention will be described below.

The random access has two access methods, that is, a Contention basedRandom Access and a Non-contention based Random. Access. The Contentionbased Random. Access is an access method with a possibility of collisionbetween the mobile station apparatuses 1 and is a random access usuallyperformed. The Non-contention based Random Access is an access method inwhich no collision occurs between the mobile station apparatuses 1 andis a random access performed under the initiative of the base stationapparatus 3 in a special case such as handover in order to rapidlysynchronize the mobile station apparatus 1 with the base stationapparatus 3.

In the random access, the mobile station apparatus 1 transmits only thepreamble for synchronization. The preamble includes a signature which isa signal pattern expressing information and can express information withseveral bits by preparing tens of types of signatures. The mobilestation apparatus 1 transmits information of 6 bits by using thepreamble, and thus 64 types of signatures are prepared.

The base station apparatus 3, when receiving the preamble transmittedfrom the mobile station apparatus 1, calculates a difference insynchronization timing between the mobile station apparatus 1 and thebase station apparatus 3 from the preamble and performs scheduling forthe mobile station apparatus 1 to transmit the message 3. Then, the basestation apparatus 3 assigns a T C-RNTI to the mobile station apparatus 1which transmitted the preamble, includes and arranges an RA-RNTI (RandomAccess-Radio Network Temporary Identifier) corresponding to the PRACHwhich received the preamble in the PDCCH and transmits a random accessresponse (message 2) including difference information for thesynchronization timing, scheduling information, the T C-RNTI and anumber of the signature of the received preamble (also referred to as arandom ID or a preamble ID) in the PDSCH indicated by the radio resourceassignment included in this PDCCH.

If it is confirmed that the RA-RNTI is included in the detected PDCCH,the mobile station apparatus 1 confirms the contents of the randomaccess response arranged in the PDSCH indicated by the radio resourceassignment included in the PDCCH. The mobile station apparatus 1extracts a response including the number of signature of the preambletransmitted by its own apparatus, corrects the difference in thesynchronization timing and transmits, by the radio resource of theassigned PUSCH and the transmission format, the message 3 including theC-RNTI notified from the base station apparatus 3 in advance or amessage requesting connection (RRC Connection Request message) or amessage requesting connection resetting (RRC Connection ReestablishmentRequest message).

The base station apparatus 3, when having received the message 3 fromthe mobile station apparatus 1, transmits, to the mobile stationapparatus 1, a contention resolution (message 4) for determining if acollision is occurring or not between the mobile station apparatuses 1by using the C-RNTI or information for identifying the mobile stationapparatus 1 and included in the message requesting connection or themessage requesting connection resetting included in the received message3. The base station apparatus 3, when failed in decoding of the message3, instructs the mobile station apparatus 1 to retransmit the message 3by using the DCI format 0 including the T C-RNTI corresponding to themessage 3 failed in decoding.

The uplink data (UL-SCH) and the downlink data (DL-SCH) and the like aretransport channels. The unit in which the uplink data is transmitted bythe PUSCH and the unit in which the downlink data is transmitted by thePDSCH are referred to as transport blocks. The transport block is a unithandled by a MAC (Media Access Control) layer, and HARQ (retransmission)control is executed for each transport block.

In a physical layer, the transport block is associated with a code word,and signal processing such as encoding is executed for each code word.The transport block size is the number of bits of the transport block.The mobile station apparatus 1 recognizes the transport block size onthe basis of the number of Physical Resource Blocks (PRB) and MCS(MCS&RV) indicated by information indicating the radio resourceassignment included in the uplink grant or the downlink assignment.

A configuration of a radio frame of the present invention will bedescribed below.

FIG. 12 is a schematic diagram illustrating an example of aconfiguration of the radio frame of the downlink in an embodiment of thepresent invention. In FIG. 12, the horizontal axis indicates the timedomain and the vertical axis indicates the frequency domain. Asillustrated in FIG. 12, the radio frame of the downlink includes aplurality of downlink physical resource block (PRB) pairs (a regionsurrounded by a broken line in FIG. 12, for example). This downlinkphysical resource block pair is a unit for assignment of the radioresource and the like and includes a frequency band having a widthdetermined in advance (PRB bandwidth; 180 kHz) and a time zone (2slots=1 subframe; 1 ms).

One downlink physical resource block pair includes two downlink physicalresource blocks (PRB bandwidth×slot) contiguous in the time domain. Onedownlink physical resource block (a unit surrounded by a bold line inFIG. 12) includes 12 subcarriers (15 kHz) in the frequency domain and 7OFDM (Orthogonal Frequency Division Multiplexing) symbols (71 μs) in thetime domain.

In the time domain, there are a slot (0.5 ms) composed of 7 OFDM symbols(71 μs), a subframe (1 ms) composed of 2 slots, and a radio frame (10ms) composed of 10 subframes. The time interval of 1 ms which is thesame as the subframe is also referred to as a transmit time interval(TTI). In the frequency domain, a plurality of the downlink physicalresource blocks is arranged in accordance with the bandwidth of thedownlink. A unit composed of one subcarrier and one OFDM symbol isreferred to as a downlink resource element.

Arrangement of the physical channel assigned to the downlink will bedescribed below. In each subframe of the downlink, the PDCCH, thePCFICH, the PHICH, the PDSCH, the downlink reference signal and the likeare arranged. The PDCCH is arranged from the first OFDM symbol in thesubframe (a hatched region in FIG. 12). The number of OFDM symbols inwhich the PDCCH is arranged is different for each subframe, andinformation indicating the number of OFDM symbols in each of which thePDCCH is arranged is broadcasted by the PCFICH. In each subframe, aplurality of PDCCHs is frequency-multiplexed and time-multiplexed.

The PCFICH is arranged in the first OFDM symbol on the subframe and isfrequency-multiplexed with the PDCCH. The PHICH is frequency-multiplexedwith the PDCCH in the same OFDM symbol (a hatched region withreticulated lines in FIG. 12). The PHICH may be arranged only in thefirst OFDM symbol on the subframe or may be arranged in a distributedmanner in a plurality of the OFDM symbols in each of which the PDCCH isarranged. In each subframe, a plurality of PHICHs isfrequency-multiplexed and code-multiplexed.

After a predetermined time from the transmission of the PUSCH (4 mslater, 4 subframes later or 4 TTIs later, for example), the mobilestation apparatus 1 receives HARQ feedback for this PUSCH in the PHICHon the subframe of the downlink. In which PHICH on the subframe of thedownlink the HARQ indicator for the PUSCH is arranged is determinedbased on a number of the physical resource block with the smallestnumber (in the lowest frequency domain) in the physical resource blocksassigned to this PUSCH and based on information included in the uplinkgrant and used for determining the cyclic shift used for the uplinkreference signal which is time-multiplexed with the PUSCH.

The PDSCH is arranged in the OFDM symbol (a non-hatched region in FIG.12) other than the OFDM symbols in which the PDCCH, the PCFICH, and thePHICH are arranged in the subframe. The radio resource of the PDSCH isassigned by using the downlink assignment. The radio resources of thePDSCH and the PDCCH including the downlink assignment used for thisassignment of the PDSCH in the time domain are arranged in the samesubframe of the downlink. In each subframe, a plurality of the PDSCHs isfrequency-multiplexed and space-multiplexed. Though the downlinkreference signal is not shown in FIG. 12 for simplification ofexplanation, the downlink reference signal is arranged in a distributedmanner in the frequency domain and the time domain.

FIG. 13 is a schematic diagram illustrating an example of aconfiguration of the radio frame of the uplink in an embodiment of thepresent invention. In FIG. 13, the horizontal axis indicates the timedomain, and the vertical axis indicates the frequency domain. Asillustrated in FIG. 13, the uplink radio frame includes a plurality ofuplink physical resource block pairs (a region surrounded by a brokenline in FIG. 13, for example). This uplink physical resource block pairis a unit for assignment of the radio resource and the like and includesa frequency band having a width determined in advance (PRB bandwidth;180 kHz) and a time zone (2 slots=1 subframe; 1 ms).

One uplink physical resource block pair includes two uplink physicalresource blocks (PRB bandwidth×slot) contiguous in the time domain. Oneuplink physical resource block (unit surrounded by a bold line in FIG.13) includes 12 subcarriers (15 kHz) in the frequency domain and 7SC-FDMA symbols (71 μs) in the time domain.

In the time domain, there are a slot (0.5 ms) composed of 7 SC-FDMA(Single-Carrier Frequency Division Multiple Access) symbols (71 μs), asubframe (1 ms) composed of two slots, and a radio frame (10 ms)composed of 10 subframes. The time interval 1 ms which is the same asthat of the subframe is also referred to as a Transmit Time Interval(TTI). In the frequency domain, a plurality of uplink physical resourceblocks is arranged in accordance with the bandwidth of the uplink. Aunit composed of one subcarrier and one SC-FDMA symbol is referred to asan uplink resource element.

The physical channel assigned in the uplink radio frame will bedescribed below. The PUCCH, PUCSH, PRACH, the uplink reference signaland the like are arranged in each subframe of the uplink. The PUCCH isarranged in the uplink physical resource block (a diagonally hatchedregion) at the both ends of the uplink band. In each subframe, aplurality of the PUCCHs is frequency-multiplexed and code-multiplexed.

The PUSCH is arranged in the uplink physical resource block pair (anon-hatched region) other than the uplink physical resource block inwhich the PUCCH is arranged. The radio resource for the PUSCH isassigned by using the uplink grant and arranged in an uplink subframeafter a predetermined time (4 ms after, 4 subframes after or 4 TTIsafter, for example) from the downlink subframe in which the PUCCHincluding this uplink grant is arranged. In each subframe, a pluralityof the PUSCHs is frequency-multiplexed and spatially-multiplexed.

Information indicating the subframe and the uplink physical resourceblock in which the PRACH is arranged is broadcasted by the base stationapparatus. The uplink reference signal is time-multiplexed with thePUCCH or the PUSCH. For example, the DMRS time-multiplexed with thePUSCH is arranged in the fourth and eleventh SC-FDMA symbols in thesubframe.

An apparatus configuration of the present invention will be describedbelow.

FIG. 1 is a schematic block diagram illustrating a configuration of amobile station apparatus 1 of an embodiment of the present invention. Asillustrated in the figure, the mobile station apparatus 1 includes ahigher-layer processing unit 101, a control unit 103, a reception unit105, a transmission unit 107, and a transmission/reception antenna 109.The higher-layer processing unit 101 includes a radio resource controlunit 1011 and a determination unit 1013. The reception unit 105 includesa decoding unit 1051, a demodulation unit 1053, a demultiplexing unit1055, a radio reception unit 1057, and a channel measurement unit 1059.The transmission unit 107 includes an encoding unit 1071, a modulationunit 1073, a multiplexing unit 1075, a radio transmission unit 1077, andan uplink reference signal generation unit 1079.

The higher-layer processing unit 101 outputs uplink data generated by anoperation of a user and the like to the transmission unit 107. Moreover,the higher-layer processing unit 101 performs processing of a MediumAccess Control (MAC) layer, a Packet Data Convergence Protocol (PDCP)layer, a Radio Link Control (RLC) layer and a Radio Resource Control(RRC) layer. Moreover, the higher-layer processing unit 101 generatescontrol information for control of the reception unit 105 and thetransmission unit 107 on the basis of the downlink control informationreceived by the PDCCH and the like and outputs the control informationto the control unit 103.

The radio resource control unit 1011 provided in the higher-layerprocessing unit 101 manages various setting information of its ownapparatus. For example, the radio resource control unit 1011 manages anRNTI such as a C-RNTI and an uplink transmission mode which will bedescribed later. Moreover, the radio resource control unit 1011generates information arranged in each channel of the uplink and outputsthe information to the transmission unit 107.

The determination unit 1013 provided in the higher-layer processing unit101 determines whether or not the cyclic shift information included inthe uplink grant corresponds to the OCC applied to the DMRS by using theuplink transmission mode, the RNTI and the like managed by the radioresource control unit 1011. Moreover, the determination unit 1013determines the cyclic shift and the OCC applied to the DMRS inaccordance with the cyclic shift information on the basis of thedetermination result, generates control information for the transmissionunit 107 to apply the determined cyclic shift and OCC to the DMRS andoutputs the control information to the control unit 103.

The control unit 103 generates a control signal for controlling thereception unit 105 and the transmission unit 107 on the basis of thecontrol information from the higher-layer processing unit 101. Thecontrol unit 103 outputs the generated control signal to the receptionunit 105 and the transmission unit 107 and controls the reception unit105 and the transmission unit 107. The reception unit 105 separates,demodulates, and decodes the received signal received from the basestation apparatus 3 via the transmission/reception antenna 109 inaccordance with the control signal input from the control unit 103 andoutputs the decoded information to the higher-layer processing unit 101.

The radio reception unit 1057 converts the downlink signal received viathe transmission/reception antenna 109 to an intermediate frequency(down convert), removes an unnecessary frequency component, controls anamplification level so that the signal level is maintainedappropriately, orthogonally demodulates the signal on the basis of anin-phase component and an orthogonal component of the received signaland converts the orthogonally-demodulated analog signal to a digitalsignal. The radio reception unit 1057 removes a portion corresponding toa Guard Interval (GI) from the converted digital signal, performs FastFourier Transform (FFT) on the signal from which the GI has beenremoved, and extracts a signal of the frequency domain.

The demultiplexing unit 1055 separates the extracted signal to thePHICH, the PDCCH, the PDSCH, and the downlink reference signal,respectively. This separation is made on the basis of assignmentinformation of a radio resource notified by the downlink assignment andthe like. Moreover, the demultiplexing unit 1055 compensates for thechannels of the PHICH, PDCCH, and PDSCH on the basis of estimationvalues of the channels input from the channel measurement unit 1059.Moreover, the demultiplexing unit 1055 outputs the separated downlinkreference signal to the channel measurement unit 1059.

The demodulation unit 1053 multiplies and synthesizes a correspondingcode to the PHICH, demodulates the synthesized signal in the BinaryPhase Shift Keying (BPSK) modulation scheme, and outputs the result tothe decoding unit 1051. The decoding unit 1051 decodes the PHICHaddressed to its own apparatus and outputs a decoded HARQ indicator tothe higher-layer processing unit 101. The demodulation unit 1053demodulates the PDCCH in a QPSK demodulation scheme and outputs theresult to the decoding unit 1051. The decoding unit 1051 tries blinddecoding of the PDCCH and if the blind decoding is successful, outputsthe decoded downlink control information and the RNTI included in thedownlink control information to the higher-layer processing unit 101.

The demodulation unit 1053 demodulates the PDSCH in a modulation schemenotified in the downlink assignment such as Quadrature Phase Shiftkeying (QPSK), 16QAM (Quadrature Amplitude Modulation), 64 QAM and thelike and outputs the result to the decoding unit 1051. The decoding unit1051 decodes the result on the basis of the information relating to thecoding rate notified in the downlink control information and outputs thedecoded downlink data (transport block) to the higher-layer processingunit 101.

The channel measurement unit 1059 measures a path loss and a channelstate of the downlink from the downlink reference signal input from thedemultiplexing unit 1055 and outputs the measured path loss and channelstate to the higher-layer processing unit 101. Moreover, the channelmeasurement unit 1059 calculates an estimation value of the downlinkchannel from the downlink reference signal and outputs the result to thedemultiplexing unit 1055.

The transmission unit 107 generates an uplink reference signal inaccordance with the control signal input form the control unit 103,encodes and modulates the uplink data (transport block) input from thehigher-layer processing unit 101, multiplexes the PUCCH, PUSCH, and thegenerated uplink reference signal, and transmits the result to the basestation apparatus 3 via the transmission/reception antenna 109. Theencoding unit 1071 performs coding on the uplink control informationinput from the higher-layer processing unit 101 such as convolutionalcoding, block coding and the like and performs turbo coding on theuplink data on the basis of the information relating to coding ratenotified in the uplink grant.

The modulation unit 1073 modulates the coding bit input from theencoding unit 1071 in a modulation scheme notified in the downlinkcontrol information such as BPSK, QPSK, 16QAM, 64QAM and the like or amodulation scheme determined in advance for each channel. The modulationunit 1073 maps sequences of modulation symbols of the plurality ofpieces of uplink data transmitted by the same PUSCH by using the MIMO SMonto a plurality of sequences larger in number than the number of thepieces of the uplink data transmitted by the same PUSCH and performsprecoding on these sequences on the basis of the number of sequencesnotified in the uplink grant and spatially multiplexed and theinformation indicating precoding to these sequences.

The uplink reference signal generation unit 1079 generates a sequenceknown to the base station apparatus 3 and acquired in compliance with arule determined in advance on the basis of a physical cell identifier(referred to as PCI, Cell ID and the like) for identifying the basestation apparatus 3, a bandwidth in which the uplink reference signal isarranged, a cyclic shift notified in the uplink grant and the like. Themultiplexing unit 1075 rearranges modulation symbols of the PUSCH toparallel in accordance with the control signal input from the controlunit 103 and then, performs Discrete Fourier Transform (DFT) thereon andmultiplexes the PUSCH and PUSCH signals with the generated uplinkreference signal for each transmission antenna port.

The radio transmission unit 1077 performs Inverse Fast Fourier Transform(IFFT) on the multiplexed signal for modulation in the SC-FDMA system,adds the guard interval to the SC-FDMA modulated SC-FDMA symbol,generates a baseband digital signal, converts the baseband digitalsignal to an analog signal, generates an in-phase component and anorthogonal component of the intermediate frequency from the analogsignal, removes an excess frequency component with respect to theintermediate frequency band, converts the signal with the intermediatefrequency to a signal with a high frequency (up convert), removes anexcess frequency component, amplifies power, and outputs the result tothe transmission/reception antenna 109 for transmission.

FIG. 2 is a schematic block diagram illustrating a configuration of thebase station apparatus 3 of an embodiment of the present invention. Asillustrated in the figure, the base station apparatus 3 includes ahigher-layer processing unit 301, a control unit 303, a reception unit305, a transmission unit 307, and a transmission/reception antenna 309.The higher-layer processing unit 301 includes a radio resource controlunit 3011 and a downlink control information generation unit 3013. Thereception unit 305 includes a decoding unit 3051, a demodulation unit3053, a demultiplexing unit 3055, a radio reception unit 3057, and achannel measurement unit 3059. The transmission unit 307 includes anencoding unit 3071, a modulation unit 3073, a multiplexing unit 3075, aradio transmission unit 3077, and a downlink reference signal generationunit 3079.

The higher-layer processing unit 301 performs processing of a Medium.Access Control (MAC) layer, a Packet Data Convergence Protocol (PDCP)layer, a Radio Link Control (RLC) layer and a Radio Resource Control(RRC) layer. Moreover, the higher-layer processing unit 301 generatescontrol information for control of the reception unit 305 and thetransmission unit 307 and outputs the control information to the controlunit 303.

The radio resource control unit 3011 provided in the higher-layerprocessing unit 301 generates or obtains from a higher node, downlinkdata (transport block), an RRC signal, and an MAC CE (Control Element)arranged in the downlink PDSCH and outputs them to the transmission unit307. Moreover, the radio resource control unit 3011 manages varioustypes of setting information of each of the mobile station apparatuses1. For example, the radio resource control unit 3011 performs managementof the RNTI such as assignment of a C-RNTI to the mobile stationapparatus 1 and of an uplink transmission mode set for the mobilestation apparatus 1.

The downlink control information generation unit 3013 provided in thehigher-layer processing unit 301 generates downlink control informationtransmitted by the PDCCH. The downlink control information generationunit 3013 generates an uplink grant including the cyclic shiftinformation corresponding to the OCC used for the DMRS and the uplinkgrant including the cyclic shift information not corresponding to theOCC used for the DMRS.

The downlink control information generation unit 3013 determines whichuplink grant is to be generated in accordance with the uplinktransmission mode set for the mobile station apparatus 1 managed by theradio resource control unit 3011, whether the uplink grant indicates apermanent radio resource of the PUSCH or the radio resource of the PUSCHonly for one subframe, whether the uplink grant indicates retransmissionof the message 3 and the like.

The control unit 303 generates a control signal for controlling thereception unit 305 and the transmission unit 307 on the basis of thecontrol information from the higher-layer processing unit 301. Thecontrol unit 303 outputs the generated control signals to the receptionunit 305 and the transmission unit 307 and controls the reception unit305 and the transmission unit 307.

The reception unit 305 separates, demodulates, and decodes a receivedsignal received from the mobile station apparatus 1 via thetransmission/reception antenna 309 in accordance with the control signalinput from the control unit 303 and outputs the decoded information tothe higher-layer processing unit 301. The radio reception unit 3057converts the uplink signal received via the transmission/receptionantenna 309 to an intermediate frequency (down convert), removes anunnecessary frequency component, controls an amplification level so thatthe signal level is maintained appropriately, orthogonally demodulatesthe signal on the basis of an in-phase component and an orthogonalcomponent of the received signal and converts theorthogonally-demodulated analog signal to a digital signal.

The radio reception unit 3057 removes a portion corresponding to a guardinterval (GI) from the converted digital signal. The radio receptionunit 3057 performs Fast Fourier Transform (FFT) on the signal from whichthe GI has been removed, extracts a signal of the frequency domain, andoutputs the result to the demultiplexing unit 3055.

The demultiplexing unit 3055 separates the signal input from the radioreception unit 3057 to the PUCCH, the PUSCH, a signal such as an uplinkreference signal and the like. This separation is performed on the basisof assignment information of a radio resource included in the uplinkgrant determined by the base station apparatus 3 in advance in the radioresource control unit 3011 and notified to each mobile station apparatus1. Moreover, the demultiplexing unit 3055 compensates for the channelsof the PUCCH and PUSCH from estimation values of the channels input fromthe channel measurement unit 3059. Moreover, the demultiplexing unit3055 outputs the separated uplink reference signal to the channelmeasurement unit 3059.

The demodulation unit 3053 performs Inverse Discrete Fourier Transform(IDFT) on the PUSCH, obtains a modulation symbol, and demodulates areceived signal for each of the modulation symbols of the PUCCH and thePUSCH using a modulation scheme determined in advance such as BPSK(Binary Phase Shift Keying), QPSK, 16QAM, 64QAM and the like or notifiedby its own apparatus in advance in the uplink grant for each of themobile station apparatuses 1. The demodulation unit 3053 separates themodulation symbols of a plurality of pieces of the uplink datatransmitted by the same PUSCH by using the MIMO SM on the basis of thenumber of sequences to be spatially multiplexed which is notified inadvance in the uplink grant for each of the mobile station apparatuses 1and information indicating precoding performed on the sequences.

The decoding unit 3051 decodes coding bits of the demodulated PUCCH andPUSCH with a coding rate determined in advance or notified in advance inthe uplink grant by its own apparatus to the mobile station apparatus 1in the coding method determined in advance and outputs the decodeduplink data and the uplink control information to the higher-layerprocessing unit 301. In the case of retransmission of the PUSCH, thedecoding unit 3051 performs decoding by using the coding bit held in aHARQ buffer input from the higher-layer processing unit 301 and thedemodulated coding bit. The channel measurement unit 3059 measuresestimation values, a channel quality and the like of the channel fromthe uplink reference signal input from the demultiplexing unit 3055 andoutputs the result to the demultiplexing unit 3055 and the higher-layerprocessing unit 301.

The transmission unit 307 generates a downlink reference signal inaccordance with the control signal input from the control unit 303,encodes and modulates the HARQ indicator, downlink control information,and the downlink data input from the higher-layer processing unit 301,multiplexes the PHICH, PDCCH, PDSCH, and the downlink reference signal,and transmits the result to the mobile station apparatus 1 via thetransmission/reception antenna 309.

The encoding unit 3071 performs coding on the HARQ indicator, thedownlink control information, and the downlink data input from thehigher-layer processing unit 301 by using a coding method determined inadvance such as block coding, convolutional coding, turbo coding and thelike or performs coding by using a coding method determined by the radioresource control unit 3011. The modulation unit 3073 modulates thecoding bits input from the encoding unit 3071 by a modulation schemedetermined in advance such as BPSK, QPSK, 16QAM, 64QAM and the like ordetermined by the radio resource control unit 3011.

The downlink reference signal generation unit 3079 generates a sequenceknown to the mobile station apparatus 1, as a downlink reference signal,acquired in compliance with a rule determined in advance on the basis ofthe physical cell identifier (PCI) for identifying the base stationapparatus 3 and the like. The multiplexing unit 3075 multiplexes thegenerated downlink reference signal with the modulated modulation symbolof each channel.

The radio transmission unit 3077 performs Inverse Fast Fourier Transform(IFFT) on the multiplexed modulation symbol and the like for performingmodulation in the OFDM system, adds the guard interval to theOFDM-modulated OFDM symbol, generates a baseband digital signal,converts the baseband digital signal to an analog signal, generates anin-phase component and an orthogonal component of the intermediatefrequency from the analog signal, removes an excess frequency componentwith respect to the intermediate frequency band, converts the signalwith the intermediate frequency to a signal with a high frequency (upconvert), removes an excess frequency component, amplifies power, andoutputs the result to the transmission/reception antenna 309 fortransmission.

FIG. 3 is a schematic diagram for explaining a generating method of theDMRS in an embodiment of the present invention. In FIG. 3, thehorizontal axis is the time domain. First, a cyclic shift is applied tothe CAZAC sequence generated by the mobile station apparatus 1 (StepS100). Subsequently, the CAZAC sequence to which the cyclic shift wasapplied is duplicated into two (Step S101) and multiplied by OCC (StepS102).

Subsequently, the CAZAC sequence multiplied by the OCC is mapped ontothe physical resource block to which the PUSCH is assigned, Inverse FastFourier Transform (IFFT) is executed, and an SC-FDMA symbol is generated(Step S103). The generated SC-FDMA symbol is mapped as fourth andeleventh SC-FDMA symbols in the subframe. Multiplication of the OCC at[1, 1] corresponds to non-application of the OCC to the DMRS (Step S102is omitted). Moreover, non-application of the OCC (Step S102 is omitted)corresponds to multiplication of the OCC at [1, 1].

A search space of the present invention will be described below.

FIG. 4 is a schematic diagram illustrating an example of a configurationof the search space in which the PDCCH of is arranged in an embodimentof the present invention. In FIG. 4, the horizontal axis indicates anumber identifying a Control Channel Element (CCE). In FIG. 4, a unitsurrounded by a bold line in FIG. 4 is a candidate in which the PDCCH isto be arranged (hereinafter referred to as “PDCCH candidate”) composedof a plurality of continuously-numbered control channel elements. ThePDCCH candidate diagonally hatched in FIG. 4 is a PDCCH candidate in amobile station apparatus specific search space (UE-specific SearchSpace: USS). The PDCCH candidate hatched in a reticulated state in FIG.4 is a PDCCH candidate in a Common Search Space (CSS).

The common search space is a space common among a plurality of themobile station apparatuses 1 and is a space in which the PDCCH to aplurality of mobile station apparatuses 1 and/or the PDCCH to a specificmobile station apparatus 1 are/is arranged. The mobile station apparatusspecific search space is a space in which the PDCCH to the specificmobile station apparatus 1 is arranged and is a space configured foreach mobile station apparatus 1.

The search space is a set of the PDCCH candidates. The PDCCH candidateis composed of a plurality of Control Channel Elements (CCE). Onecontrol channel element is composed of a plurality of resource elementsdispersed in a frequency domain and a time domain within the OFDM symbolin which the PDCCH in the same subframe is arranged.

Regarding the search space, a different search space is configured foreach number of the control channel elements constituting the PDCCHcandidate. In FIG. 4, different common search spaces are configured forthe PDCCH candidate constituted by four control channel elements and thePDCCH candidate constituted by eight control channel elements. Regardingthe mobile station apparatus specific search space, different mobilestation apparatus specific search spaces are configured for the PDCCHcandidate constituted by one control channel element, the PDCCHcandidate constituted by two control channel elements, the PDCCHcandidate constituted by four control channel elements, and the PDCCHcandidate constituted by eight channel elements.

The common search space is configured by zeroth to fifteenth controlchannel elements. The number of PDCCH candidates and the number ofcontrol channel elements constituting the mobile station apparatusspecific search space are determined in advance, and the number of thecontrol channel element constituting the mobile station apparatusspecific search space is determined by hushing function using the C-RNTIassigned by the base station apparatus 3 to the mobile station apparatus1 as an input. Moreover, the mobile station apparatus specific searchspace is constituted by control channel elements different for eachsubframe.

A part of or the whole of the different mobile station apparatusspecific search spaces may be duplicated for the different mobilestation apparatus 1. The plurality of mobile station apparatus specificsearch spaces and the plurality of common search spaces constituted bythe different numbers of the control channel elements for the samemobile station apparatus 1 may be constituted by the same controlchannel element or may be constituted by the different control channelelements. That is, a part of or the whole of the PDCCH candidatesconstituting the different plurality of search spaces may be duplicated.

An uplink transmission mode of the present invention will be describedbelow.

FIG. 5 is a diagram illustrating a relationship between the uplink grantand the OCC applied to the DMRS in an embodiment of the presentinvention. The mobile station apparatus 1 of the present inventionincludes a mode 1 not using the OCC for the DMRS time-multiplexed withthe PUSCH and a mode 2 using the OCC for the DMRS time-multiplexed withthe PUSCH as the uplink transmission mode. The uplink transmission modeof the mobile station apparatus 1 is set by the base station apparatus3. The base station apparatus 3 notifies the mobile station apparatus 1of information indicating the set uplink transmission mode by using anRRC (Radio Resource Control) signal or the like. The RRC signal isinformation used for control of radio resources and transmitted by thePDSCH.

The mobile station apparatus 1 performs blind decoding for the DCIformat 0 including the C-RNTI, the DCI format 0 including the SPSC-RNTI, and the DCI format 0 including the T C-RNTI in the uplinktransmission mode 1 in the common search space and performs blinddecoding for the DCI format 0 including the C-RNTI and the DCI format 0including the SPS C-RNTI in the mobile station apparatus specific searchspace.

In the mobile station apparatus 1 in the mode 1, whichever of the RNTIis included in the DCI format 0, the OCC is invalid. The OCC beinginvalid means that the cyclic shift information included in the uplinkgrant is not associated with the OCC used for the DMRS. The OCC beingvalid means that the cyclic shift information included in the uplinkgrant is associated with the OCC used for the DMRS.

The mobile station apparatus 1 in the mode 2 performs blind decoding forthe DCI format 0 including the C-RNTI, the DCI format 0 including theSPS C-RNTI, and the DCI format 0 including the T C-RNTI in the commonsearch space and performs blind decoding for the DCI format 0 and theDCI format 0A including the C-RNTI and the DCI format 0 and the DCIformat 0A including the SPS C-RNTI in the mobile station apparatusspecific search space.

The mobile station apparatus 1 in the mode 2 determines whether the OCCis valid or invalid on the basis of which of the RNTI is included in theuplink grant (in the DCI format 0 and the DCI format 0A). The mobilestation apparatus 1 in the mode 2 determines that the OCC is valid ifthe C-RNTI is included in the uplink grant.

Moreover, if the SPS C-RNTI is included in the uplink grant and thisuplink grant instructs to retransmit the permanently assigned PUSCH, themobile station apparatus 1 in the mode 2 determines that the OCC isvalid. If the uplink grant including the SPS C-RNTI does not instruct toretransmit, the mobile station apparatus 1 in the mode 2 determines thatthe OCC is invalid.

If the uplink grant including the SPS C-RNTI instructs to retransmit thepermanently assigned PUSCH, a value of an NDI of this uplink grant isset to one. If the uplink grant including the SPS C-RNTI instructs toperform activation (or initiation), resetting or release of assignmentof the permanently assigned PUSCH, the value of the NDI of this uplinkgrant is set to zero.

Moreover, if the uplink grant including the SPS C-RNTI does not instructto retransmit, that is, if the value of the NDI is zero, the cyclicshift information included in the uplink grant is set to a specific codepoint (‘000’, for example). The period of the radio resource of thePUSCH permanently assigned to the mobile station apparatus 1 or the likeis notified from the base station apparatus 3 to the mobile stationapparatus 1 in advance by the RRC signal.

The T C-RNTI is used for instructing the mobile station apparatus 1 toperform retransmission of the random access message 3. However, sincethe base station apparatus 3 failed in decoding the message 3 includingthe information for identifying the mobile station apparatus 1, the basestation apparatus 3 cannot recognize which mobile station apparatus 1has transmitted the message 3.

If the mobile station apparatus 1 in the mode 1 invalidates the OCC andperforms retransmission of the message 3 and the mobile stationapparatus 1 in the mode 2 validates the OCC and transmits the message 3,since the base station apparatus 3 cannot determine whether or not theOCC is applied to the DMRS time-multiplexed with the PUSCH of themessage 3 and transmitted, the channel compensation cannot be correctlyperformed on the PUSCH, and whereby a problem that reception of themessage 3 fails is caused.

Then, the mobile station apparatus 1 in the mode 2 determines that theOCC is invalid if the T C-RNTI is included in the DCI format 0 and makestransmission without applying the OCC to the DMRS when retransmittingthe message 3. Moreover, the mobile station apparatus 1 also makestransmission without applying the OCC to the DMRS when making initialtransmission of the message 3 on the radio resource assigned by a randomaccess response for the random access preamble transmitted by its ownapparatus. As a result, the base station apparatus 3 can correctlyreceive the message 3 by determining that the OCC is never used in themessage 3.

In the mobile station apparatus specific search space to the mobilestation apparatus 1 in the mode 2, only the DCI format 0 or only the DCIformat 0A may be arranged as the uplink grant. In the common searchspace and/or the mobile station apparatus specific search space, the DCIformat other than the DCI formats illustrated in FIG. 5 may be arrangedor the DCI format including the RNTI other than the RNTI illustrated inFIG. 5 may be arranged.

FIG. 6 is a diagram illustrating the relationship between the cyclicshift information and the cyclic shift applied to the DMRS when themobile station apparatus 1 of an embodiment of the present inventiondetermines that the OCC is invalid. When the mobile station apparatus 1determines that the OCC is invalid, it selects only a parameter fordetermining the cyclic shift to be applied to the DMRS on the basis ofthe cyclic shift information.

FIG. 7 is a diagram illustrating the relationship between the cyclicshift information and the cyclic shift applied to the DMRS when themobile station apparatus 1 of an embodiment of the present inventiondetermines that the OCC is valid. When the mobile station apparatus 1determines that the OCC is valid, it selects the parameter fordetermining the cyclic shift to be applied to the DMRS and the OCC to beapplied to the DMRS on the basis of the cyclic shift information.

If the base station apparatus 3 changes setting of the uplinktransmission mode of the mobile station apparatus 1 and notifies themobile station apparatus 1 to change the setting of the uplinktransmission mode by the RRC signal, the mobile station apparatus 1changes the uplink transmission mode after a certain time has elapsedsince reception of this RRC signal. After changing the uplinktransmission mode, the mobile station apparatus 1 notifies the basestation apparatus 3 of a message notifying that the change of the uplinktransmission mode is completed.

Since the base station apparatus 3 cannot know when the mobile stationapparatus 1 changed the uplink transmission mode for a period fromnotification of a change of the uplink transmission mode to the mobilestation apparatus 1 by the RRC signal to reception of the message fromthe mobile station apparatus 1 notifying that the change of the uplinktransmission mode is completed, a period during which the uplinktransmission mode of the mobile station apparatus 1 cannot be grasped isgenerated.

As described above, in a period during which the base station apparatus3 cannot grasp the uplink transmission mode of the mobile stationapparatus 1, the base station apparatus 3 includes the cyclic shiftinformation having a value corresponding to the OCC at [1, 1] having thesame DMRS when the OCC is invalidated in the DCI format and transmitsthe result to the mobile station apparatus 1 in the mode 2. In FIG. 7,the cyclic shift information having values of “000”, “001”, “011”, and“110” corresponds to the OCC at [1, 1].

As a result, even if the uplink transmission mode of the mobile stationapparatus 1 is the mode 2 and the OCC has been validated in the periodduring which the base station apparatus 3 cannot grasp the uplinktransmission mode of the mobile station apparatus 1, the mobile stationapparatus 1 uses only the OCC at [1, 1] having the same DMRS when theOCC is invalidated, and thus, regardless of the uplink transmission modeof the mobile station apparatus 1, the base station apparatus 3 cancorrectly receive the PUSCH by performing reception processing of thePUSCH, assuming that the mobile station apparatus 1 is not using theOCC.

If the base station apparatus 3 does not know the uplink transmissionmode of the mobile station apparatus 1 when the mobile station apparatus1 makes an initial access to the base station apparatus 3, the basestation apparatus 3 cannot correctly receive the PUSCH transmitted bythe mobile station apparatus 1, and thus, a default uplink transmissionmode needs to be determined. In the present invention, the uplinktransmission mode of the mobile station apparatus 1 when the mobilestation apparatus 1 makes an initial access to the base stationapparatus 3 is set to the mode 1 whose transmission processing of theDMRS is easy.

An operation of the apparatus of the present invention will be describedbelow.

FIG. 8 is a flowchart illustrating an example of the operation of themobile station apparatus 1 of an embodiment of the present invention.The mobile station apparatus 1 sets the uplink transmission modenotified from the base station apparatus 3 (Step S200). The mobilestation apparatus 1 performs blind decoding of the uplink grant anddetects the uplink grant (Step S201). The mobile station apparatus 1determines whether the uplink transmission mode of its own apparatus isthe mode 1 or the mode 2 (Step S202). If the mobile station apparatus 1determines that the uplink transmission mode of its own apparatus is themode 2, it determines whether the OCC is to be applied to the DMRS onthe basis of the RNTI included in the uplink grant (Step S203).

If the uplink grant includes the SPS C-RNTI assigned to its ownapparatus and retransmission is ordered and if the uplink grant includesthe C-RNTI assigned to its own apparatus, the mobile station apparatus 1determines the OCC and the cyclic shift to be applied to the DMRS on thebasis of the cyclic shift information in the uplink grant (Step S204).

If the uplink grant includes the SPS C-RNTI assigned to its ownapparatus and retransmission is not ordered, or if the uplink grantincludes the T C-RNTI corresponding to the random access message 3, themobile station apparatus 1 determines only the cyclic shift to beapplied to the DMRS on the basis of the cyclic shift information in theuplink grant (Step S205).

If the mobile station apparatus 1 determines that the uplinktransmission mode of its own apparatus is the mode 1 at Step S202, theroutine proceeds to Step S205. The mobile station apparatus 1 appliesthe cyclic shift and the OCC, as necessary, determined at Step S204 orStep S205 to the DMRS, time-multiplexes the DMRS and PUSCH and transmitsthe result (Step S206).

FIG. 9 is a flowchart illustrating an example of an operation of thebase station apparatus 3 of an embodiment of the present invention. Thebase station apparatus 3 notifies the mobile station apparatus 1 of thetransmission mode set for the mobile station apparatus 1 by using theRRC signal or the like (Step S300).

The base station apparatus 3 schedules the PUSCH and transmits theuplink grant indicating the radio resource for the scheduled PUSCH tothe mobile station apparatus 1 (Step S301). The base station apparatus 3includes the cyclic shift information corresponding only to theparameter for determining the cyclic shift used for the DMRS in theuplink grant corresponding to the mobile station apparatus 1 set to themode 1. The base station apparatus 3 includes the cyclic shiftinformation corresponding only to the parameter for determining thecyclic shift used for the DMRS in the uplink grant assigning the radioresource of the PUSCH used for retransmitting the message 3 including TC-RNTI.

The base station apparatus 3 includes the cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe DMRS and the OCC used for the DMRS in the uplink grant includingC-RNTI corresponding to the mobile station apparatus 1 set to the mode2. The base station apparatus 3 includes the cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe DMRS and the OCC used for the DMRS in the uplink grant including theSPS C-RNTI and ordering retransmission of the PUSCH corresponding to themobile station apparatus 1 set to the mode 2.

The base station apparatus 3 includes the cyclic shift informationcorresponding only to the parameter for determining the cyclic shiftused for the DMRS in the uplink grant including the SPS C-RNTI and notordering retransmission of the PUSCH corresponding to the mobile stationapparatus 1 set to the mode 2. The base station apparatus 3 receives thePUSCH and the DMRS in compliance with the uplink grant transmitted tothe mobile station apparatus 1 at Step S301, performs channelcompensation of the PUSCH by using the DMRS, and executes decodingprocessing of the PUSCH (Step S302).

As described above, in the embodiment of the present invention, in theradio communication system in which the base station apparatus 3 and themobile station apparatus 1 perform radio communication with each other,the base station apparatus 3 transmits the uplink grant (first controlinformation) including the cyclic shift information corresponding to theparameter for determining the cyclic shift used for the DMRS (referencesignal) time-multiplexed with the PUSCH (data channel) and transmittedby the mobile station apparatus 1 and the uplink grant (second controlinformation) including the above-described cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe DMRS and the OCC (diffusion code) used for the DMRS by includingdifferent RNTI (identifier) therein.

Then, the mobile station apparatus 1 determines by the RNTI included inthe detected uplink grant whether the cyclic shift information includedin the detected uplink grant corresponds to the parameter fordetermining the cyclic shift used for the DMRS time-multiplexed with thePUSCH and the OCC used for the DMRS or corresponds only to the parameterfor determining the cyclic shift used for the DMRS time-multiplexed withthe PUSCH.

As a result, the base station apparatus 3 can accurately recognizewhether or not the mobile station apparatus 1 applies the OCC to theDMRS time-multiplexed with the PUSCH, and thus, the base stationapparatus 3 can correctly perform channel compensation of the PUSCH byusing the DMRS and decode the PUSCH.

Second Embodiment

A second embodiment of the present invention will be described below indetail by referring to the attached drawings.

In the second embodiment of the present invention, the base stationapparatus 3 arranges the uplink grant (first control information)including the cyclic shift information corresponding only to theparameter for determining the cyclic shift used for the DMRS in thecommon search space (first search space) and arranges the uplink grant(second control information) including the cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe DMRS and the OCC used for the DMRS in the mobile station apparatusspecific search space (second search space).

In the second embodiment of the present invention, the mobile stationapparatus 1 discriminates whether the cyclic shift information includedin the detected uplink grant corresponds only to the parameter fordetermining the cyclic shift used for the DMRS or corresponds to theparameter for determining the cyclic shift used for the DMRS and the OCCused for the DMRS on the basis of which of the common search space andthe mobile station apparatus specific search space the uplink grant isdetected in.

FIG. 10 is a diagram illustrating a relationship between the uplinkgrant and the OCC applied to the DMRS in the second embodiment of thepresent invention. The mobile station apparatus 1 of the secondembodiment includes the mode 1 not using the OCC for the DMRStime-multiplexed with the PUSCH and the mode 2 using the OCC for theDMRS time-multiplexed with the PUSCH as the uplink transmission mode.

The mobile station apparatus 1 performs blind decoding in the DCI format0 including the C-RNTI, the DCI format 0 including the SPS C-RNTI, andthe DCI format 0 including the T C-RNTI in the common search space andperforms blind decoding in the DCI format 0 including the C-RNTI and theDCI format 0 including the SPS C-RNTI in the mobile station apparatusspecific search space in the uplink transmission mode 1. In mode 1,whichever of the search spaces the DCI format 0 is detected, the OCC isinvalid.

The mobile station apparatus 1 in the uplink transmission mode 2performs blind decoding in the DCI format 0 including the C-RNTI, theDCI format 0 including the SPS C-RNTI, and the DCI format 0 includingthe T C-RNTI in the common search space and performs blind decoding inthe DCI format 0 and the DCI format 0A including the C-RNTI and the DCIformat 0 and the DCI format 0A including the SPS C-RNTI in the mobilestation apparatus specific search space.

The mobile station apparatus 1 in the mode 2 determines whether the OCCis valid or invalid on the basis of which of the common search space orthe mobile station apparatus specific search space the DCI format 0 andthe DCI format 0A are detected in. The mobile station apparatus 1 in themode 2 determines that the OCC is invalid if the DCI format 0 isdetected in the common search space. The mobile station apparatus 1 inthe mode 2 determines that the OCC is valid if the DCI format 0 and theDCI format 0A including the C-RNTI are detected in the mobile stationapparatus specific search space. Since the mobile station apparatus 1 inthe mode 2 monitors the DCI format 0A only in the mobile stationapparatus specific search space, the DCI format 0A has the OCC valid allthe time.

The mobile station apparatus 1 in the mode 2 determines that the OCC isvalid if the DCI format 0 and the DCI format 0A including the SPS C-RNTIand ordering retransmission are detected in the mobile station apparatusspecific search space. The mobile station apparatus 1 in the mode 2determines that the OCC is invalid if the DCI format 0 and the DCIformat 0A including the SPS C-RNTI and not ordering retransmission aredetected in the mobile station apparatus specific search space.

If at least a part of the common search space and the mobile stationapparatus specific search space are overlapped, there is a problem thatthe mobile station apparatus 1 cannot determine whether the DCI format 0detected in the overlapped space is arranged in the common search spaceand the OCC is invalid or it is arranged in the mobile station apparatusspecific search space and the OCC is valid.

The overlap of the common search space and the mobile station apparatusspecific search space means that the PDCCH candidates constituting thecommon search space and the PDCCH candidates constituting the mobilestation apparatus specific search space are all composed of the samecontrol channel elements. In FIG. 4, the PDCCH candidate composed ofeighth to fifteenth control channel elements is a space where the commonsearch space and the mobile station apparatus specific search space areoverlapped.

Then, in the present invention, if the DCI format 0 being able to bearranged in both the common search space and the mobile stationapparatus specific search space is to be arranged in a space where thecommon search space and the mobile station apparatus specific searchspace are overlapped, in which of the search spaces the DCI format 0 isarranged is determined in advance. If the mobile station apparatus 1detects the DCI format 0 being able to be arranged in both the commonsearch space and the mobile station apparatus specific search space inthe space where the common search space and the mobile station apparatusspecific search space are overlapped, the mobile station apparatus 1determines that it is the DCI format to be arranged in the search spacedetermined in advance.

If the DCI format 0 is detected in the space where the common searchspace and the mobile station apparatus specific search space areoverlapped, for example, it is determined in advance that the DCI format0 is to be arranged in the common search space and the mobile stationapparatus 1 determines that the OCC is invalid.

As a result, in the period from transmission of the RRC signalinstructing the mobile station apparatus 1 to change the uplinktransmission mode to reception of the message from the mobile stationapparatus 1 notifying that the change of the uplink transmission modehas been completed when the base station apparatus 3 can not grasp theuplink transmission mode of the mobile station apparatus 1, the mobilestation apparatus 1 determines that the OCC is invalid all the timeregardless of the uplink transmission mode by using the DCI format 0arranged in the common search space and thus, the base station apparatus3 can correctly recognize whether or not the mobile station apparatus 1applies the OCC to the DMRS time-multiplexed with the PUSCH.

Since the base station apparatus 3 can perform radio communication withthe mobile station apparatus 1 by using the uplink grant including theC-RNTI in the common search space in the above period, the OCC of theuplink grant including the SPS C-RNTI in the common search space may bemade valid.

Moreover, the present invention may employ the following mode. That is,the radio communication system of the present invention is a radiocommunication system in which the base station apparatus and the mobilestation apparatus perform radio communication with each other, whereinthe base station apparatus includes the cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe reference signal transmitted from the mobile station apparatus inthe first control information, includes the cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe reference signal and the spread code used for the reference signalin the second control information and transmits the first controlinformation or the second control information to the mobile stationapparatus, while the mobile station apparatus applies only the cyclicshift to the reference signal in case that the first control informationwas detected, applies the cyclic shift and the spread code to thereference signal and transmits the reference signal in case that thesecond control information was detected.

Moreover, in the radio communication system of the present invention,the base station apparatus includes the first RNTI in the first controlinformation and includes the second RNTI in the second controlinformation, while the mobile station apparatus discriminates whetherthe detected control information is the first control information or thesecond control information on the basis of whether the detected controlinformation includes the first RNTI or the second RNTI.

Furthermore, in the radio communication system of the present invention,the base station apparatus sets the first mode in which the mobilestation apparatus is made to monitor only the first control informationor the second mode in which the mobile station apparatus is made tomonitor at least the second control information and transmits only thecyclic shift information corresponding to the spread signal at [1, 1]included in the second control information for a period fromnotification of the setting to the mobile station apparatus to receptionof the message notifying that the setting is completed from the mobilestation apparatus.

Moreover, in the radio communication system of the present invention,the base station apparatus arranges the first control information in thefirst search space and arranges the second control information in thesecond search space, while the mobile station apparatus discriminateswhich of the first control information and the second controlinformation is the detected control information on the basis of which ofthe first search space and the second search space the controlinformation is detected in.

In addition, in the radio communication system of the present invention,in the space where the first search space and the second search spaceare overlapped, the base station apparatus arranges only the firstcontrol information or second control information, while, if the controlinformation is detected in the overlapped space, the mobile stationapparatus determines that the first control information or the secondcontrol information is detected.

Moreover, the base station apparatus of the present invention is a basestation apparatus that performs radio communication with the mobilestation apparatus, wherein the base station apparatus includes thecyclic shift information corresponding to the parameter for determiningthe cyclic shift used for the reference signal transmitted by the mobilestation apparatus in the first control information, includes theparameter for determining the cyclic shift used for the reference signaland the cyclic shift information corresponding to the spread code usedfor the reference signal in the second control information, andtransmits the first control information or the second controlinformation to the mobile station apparatus.

Furthermore, the mobile station apparatus of the present invention is amobile station apparatus that performs radio communication with the basestation apparatus, wherein, in case that the first control informationincluding the cyclic shift information corresponding to the parameterfor determining the cyclic shift used for the reference signaltransmitted by its own apparatus was detected, the mobile stationapparatus applies only the cyclic shift to the reference signal, whilein case that the second control information including the parameter fordetermining the cyclic shift used for the reference signal and thecyclic shift information corresponding to the spread code used for thereference signal was detected, the cyclic shift and the spread code areapplied to the reference signal, and the reference signal istransmitted.

Moreover, the radio communication method of the present invention is aradio communication method used in the base station apparatus thatperforms radio communication with the mobile station apparatus andincludes the steps of including the cyclic shift informationcorresponding to the parameter for determining the cyclic shift used forthe reference signal transmitted by the mobile station apparatus in thefirst control information, including the parameter for determining thecyclic shift used for the reference signal and the cyclic shiftinformation corresponding to the spread code used for the referencesignal in the second control information, and transmitting the firstcontrol information or the second control information to the mobilestation apparatus.

Furthermore, the radio communication method of the present invention isa radio communication method used in the mobile station apparatus thatperforms radio communication with the base station apparatus andincludes the steps of applying, if the first control informationincluding the cyclic shift information corresponding to the parameterfor determining the cyclic shift used for the reference signaltransmitted by its own apparatus was detected, only the cyclic shift tothe reference signal, applying, if the second control informationincluding the parameter for determining the cyclic shift used in thereference signal and the cyclic shift information corresponding to thespread code used for the reference signal was detected, the cyclic shiftand the spread code to the reference signal, and transmitting thereference signal.

In addition, the integrated circuit of the present invention is anintegrated circuit used in the base station apparatus that performsradio communication with the mobile station apparatus and includesfunctions of including the cyclic shift information corresponding to theparameter for determining the cyclic shift used for the reference signaltransmitted by the mobile station apparatus in the first controlinformation, including the parameter for determining the cyclic shiftused for the reference signal and the cyclic shift informationcorresponding to the spread code used for the reference signal in thesecond control information, and transmitting the first controlinformation or the second information to the mobile station apparatus.

Moreover, the integrated circuit of the present invention is anintegrated circuit used in the mobile station apparatus that performsradio communication with the base station apparatus and includesfunctions applying, if the first control information including thecyclic shift information corresponding to the parameter for determiningthe cyclic shift used for the reference signal transmitted by its ownapparatus was detected, only the cyclic shift to the reference signal,applying, if the second control information including the parameter fordetermining the cyclic shift used in the reference signal and the cyclicshift information corresponding to the spread code used for thereference signal was detected, the cyclic shift and the spread code tothe reference signal, and transmitting the reference signal.

The program operated in the base station apparatus 3 and the mobilestation apparatus 1 relating to the present invention may be a program(a program for having a computer function) for controlling the CPU(Central Processing Unit) and the like so that the functions of theabove-described embodiment relating to the present invention arerealized. The information handled by these apparatuses is temporarilystored in a RAM (Random Access Memory) during the processing thereof,and then, stored in various ROMs such as a Flash ROM (Read Only Memory)and HDDs (Hard Disk Drive), and read out, modified/written by the CPU asnecessary.

A part of the mobile station apparatus 1 and the base station apparatus3 in the above-described embodiment may be realized by a computer. Inthat case, the program for realizing the control function is recorded ina computer-readable recording medium, and the program recorded in therecording medium may be read in and executed by the computer system soas to be realized.

The “computer system” here means a computer system incorporated in themobile station apparatus 1 or the base station apparatus 3 and isassumed to include OS and hardware such as peripheral equipment.Moreover, the “computer-readable recording medium” refers to a portablemedium such as a flexible disk, a magneto optical disk, a ROM, a CD-ROMand the like and a storage device such as a hard disk incorporated inthe computer system.

Moreover, the “computer-readable recording medium” may include thoseholding the program dynamically for a short time such as a communicationline when the program is transmitted through a communication line suchas a network including the Internet and a telephone line and the likeand those holding the program for a given time such as a volatile memoryinside the computer system which becomes a server and a client in thatcase. Moreover, the above-described programs may be such as to realize apart of the above-described functions or may be able to be realized by acombination with the program already recorded in the computer system.

Furthermore, a part of or the whole of the mobile station apparatus 1and the base station apparatus 3 in the above-described embodiment maybe realized as an LSI which is typically an integrated circuit or may berealized as a chip set. Each functional block of the mobile stationapparatus 1 and the base station apparatus 3 may be individually madeinto a chip or a part of or the whole of them may be integrated and madeinto a chip. Moreover, a method of making them into an integratedcircuit is not limited to the LSI but may be realized by a dedicatedcircuit or a general-purpose processor. Moreover, if a technology ofmaking an integrated circuit which replaces the LSI emerges due to aprogress in the semiconductor technology, the integrated circuit by thattechnology can be also used.

The embodiment of this invention has been described in detail byreferring to the attached drawings, but the specific configuration isnot limited to those described above but is capable of various designchanges and the like within a range not departing from the gist of thisinvention.

REFERENCE SIGNS LIST

-   1 (1A, 1B, 1C) mobile station apparatus-   3 base station apparatus-   101 higher layer processing unit-   103 control unit-   105 reception unit-   107 transmission unit-   301 higher layer processing unit-   303 control unit-   305 reception unit-   307 transmission unit-   1011 radio resource control unit-   1013 determination unit-   3011 radio resource control unit-   3013 downlink control information generation unit

The invention claimed is:
 1. A terminal apparatus that communicates witha base station apparatus, comprising: a generation unit configured togenerate a demodulation reference signal on the basis of a demodulationreference signal sequence given by multiplying a reference signalsequence by a certain sequence, the demodulation reference signal beingassociated with a transmission of a physical uplink shared channel, anda reception unit configured to receive downlink control information,wherein for a downlink control information format 0: the certainsequence is [1 1] in a case where a parameter associated with theorthogonal cover code for the demodulation reference signal is not setor in a case where a temporary Cell-Radio Network Temporary Identity(C-NRTI) was used to transmit the downlink control information; and thecertain sequence is one of [1 1] and [1 −1], and is based on cyclicshift information in the downlink control information, in a case wherethe parameter associated with the orthogonal cover code for thedemodulation reference signal is set and the temporary C-RNTI was notused to transmit the downlink control information.
 2. The terminalapparatus according claim 1, wherein the terminal apparatus furthercomprising: a transmission unit configured to transmit the demodulationreference signal together with the physical uplink shared channelscheduled by the downlink control information.
 3. The terminal apparatusaccording claim 1, wherein the downlink control information istransmitted by means of the downlink control information format 0 and isused for scheduling of the physical uplink shared channel transmitted ona single antenna port.
 4. A base station apparatus that communicateswith a terminal apparatus, comprising: a transmission unit configured totransmit downlink control information, and a reception unit configuredto receive a demodulation reference signal associated with atransmission of a physical uplink shared channel, the demodulationreference signal being generated on the basis of a demodulationreference signal sequence given by multiplying a reference signalsequence by a certain sequence, wherein for a downlink controlinformation format 0: the certain sequence is [1 1] in a case where aparameter associated with the orthogonal cover code for the demodulationreference signal is not set or in a case where a temporary Cell-RadioNetwork Temporary Identity (C-NRTI) was used to transmit the downlinkcontrol information; and the certain sequence is one of [1 1] and [1−1], and is based on cyclic shift information in the downlink controlinformation, in a case where the parameter associated with theorthogonal cover code for the demodulation reference signal is set andthe temporary C-RNTI was not used to transmit the downlink controlinformation.
 5. The base station apparatus according claim 4, whereinthe terminal apparatus further comprising: a transmission unitconfigured to transmit the demodulation reference signal together withthe physical uplink shared channel scheduled by the downlink controlinformation.
 6. The base station apparatus according claim 4, whereinthe downlink control information is transmitted by means of the downlinkcontrol information format 0 and is used for scheduling of the physicaluplink shared channel transmitted on a single antenna port.
 7. Aterminal apparatus that communicates with a base station apparatus,comprising: a reception unit configured to receive radio resourcecontrol information which indicates whether an orthogonal cover code isused for a demodulation reference signal used to demodulate a physicaluplink shared channel or not and downlink control information used forscheduling of the physical uplink shared channel transmitted on a singleantenna port, a radio resource control unit configured to set whetherthe orthogonal cover code is used for the demodulation reference signalon the basis of the received radio resource control information or not,a generation unit configured to generate the demodulation referencesignal on the basis of a demodulation reference signal sequence given bymultiplying a reference signal sequence by a certain sequence, atransmission unit configured to transmit the demodulation referencesignal together with the physical uplink shared channel scheduled by thedownlink control information, wherein the certain sequence associatedwith the generation of the demodulation reference signal transmittedtogether with the physical uplink shared channel scheduled by thedownlink control information is [1 1] in a case where the radio resourcecontrol unit sets that the orthogonal cover code is not used for thedemodulation reference signal on the basis of the received radioresource control information, the certain sequence associated with thegeneration of the demodulation reference signal transmitted togetherwith the physical uplink shared channel scheduled by the downlinkcontrol information is [1 1] in a case where the temporary Cell-RadioNetwork Temporary Identity (C-NRTI) was used to transmit the downlinkcontrol information, the certain sequence associated with the generationof the demodulation reference signal transmitted together with thephysical uplink shared channel scheduled by the downlink controlinformation is one of [1 1] and [1 −1] and is specified on the basis ofcyclic shift information included in the downlink control information ina case where the radio resource control unit sets that the orthogonalcover code is used for the demodulation reference signal on the basis ofthe received radio resource control information and the temporary C-RNTIwas not used to transmit the downlink control information.
 8. Theterminal apparatus according to claim 7, wherein the certain sequenceassociated with the generation of the demodulation reference signaltransmitted together with the physical uplink shared channel scheduledby the downlink control information is [1 1] until the radio resourcecontrol unit sets whether the orthogonal cover code is used for thedemodulation reference signal on the basis of the received radioresource control information or not.
 9. A base station apparatus thatcommunicates with a terminal apparatus, comprising: a radio resourcecontrol unit configured to maintain whether the terminal apparatus usesa orthogonal cover code for a demodulation reference signal used todemodulate a physical uplink shared channel or not, a transmission unitconfigured to transmit radio resource control information whichindicates whether the orthogonal cover code is used for the demodulationreference signal or not and downlink control information used forscheduling of the physical uplink shared channel transmitted on a singleantenna port, a reception unit configured to receive the demodulationreference signal together with the physical uplink shared channelscheduled by the downlink control information and demodulate thephysical uplink shared channel by using the demodulation referencesignal, the demodulation reference signal being generated on the basisof a demodulation reference signal sequence given by multiplying areference signal sequence by a certain sequence, the certain sequenceassociated with the generation of the demodulation reference signalreceived together with the physical uplink shared channel scheduled bythe downlink control information is [1 1] in a case where the terminalapparatus does not use the orthogonal cover code for the demodulationreference signal, the certain sequence associated with the generation ofthe demodulation reference signal received together with the physicaluplink shared channel scheduled by the downlink control information is[1 1] in a case where the temporary Cell-Radio Network TemporaryIdentity (C-NRTI) was used to transmit the downlink control information,the certain sequence associated with the generation of the demodulationreference signal received together with the physical uplink sharedchannel scheduled by the downlink control information is selectedbetween [1 1] and [1 −1] on the basis of cyclic shift informationincluded in the downlink control information in a case where theterminal apparatus uses the orthogonal cover code for the demodulationreference signal and the temporary C-RNTI was not used to transmit thedownlink control information.
 10. The base station apparatus accordingto claim 9, wherein the certain sequence associated with the generationof the demodulation reference signal received together with the physicaluplink shared channel scheduled by the downlink control information is[1 1] until the radio resource control information is transmitted.
 11. Aradio communication method used in a mobile station apparatus, themethod comprising the step of: receiving radio resource controlinformation which indicates whether an orthogonal cover code is used fora demodulation reference signal used to demodulate a physical uplinkshared channel or not and downlink control information used forscheduling of the physical uplink shared channel transmitted on a singleantenna port, setting whether the orthogonal cover code is used for thedemodulation reference signal on the basis of the received radioresource control information or not, generating the demodulationreference signal on the basis of the a demodulation reference signalsequence given by multiplying a reference signal sequence by a certainsequence, transmitting the demodulation reference signal together withthe physical uplink shared channel scheduled by the downlink controlinformation, wherein the certain sequence associated with the generationof the demodulation reference signal transmitted together with thephysical uplink shared channel scheduled by the downlink controlinformation is [1 1] in a case where setting the orthogonal cover codeis not used for the demodulation reference signal on the basis of thereceived radio resource control information, the certain sequenceassociated with the generation of the demodulation reference signaltransmitted together with the physical uplink shared channel scheduledby the downlink control information is [1 1] in a case where thetemporary Cell-Radio Network Temporary Identity (C-NRTI) was used totransmit the downlink control information, the certain sequenceassociated with the generation of the demodulation reference signaltransmitted together with the physical uplink shared channel scheduledby the downlink control information is one of [1 1] and [1 −1] and isspecified on the basis of cyclic shift information included in thedownlink control information in a case where setting the orthogonalcover code is used for the demodulation reference signal on the basis ofthe received radio resource control information and the temporary C-RNTIwas not used to transmit the downlink control information.
 12. A radiocommunication method used in a base station apparatus, the methodcomprising the step of: transmitting radio resource control informationwhich indicates whether the orthogonal cover code is used for thedemodulation reference signal or not and downlink control informationused for scheduling of the physical uplink shared channel transmitted ona single antenna port, receiving the demodulation reference signaltogether with the physical uplink shared channel scheduled by thedownlink control information and demodulating the physical uplink sharedchannel by using the demodulation reference signal, the demodulationreference signal being generated on the basis of the a demodulationreference signal sequence given by multiplying a reference signalsequence by a certain sequence, the certain sequence associated with thegeneration of the demodulation reference signal received together withthe physical uplink shared channel scheduled by the downlink controlinformation is [1 1] in a case where the terminal apparatus does not usethe orthogonal cover code for the demodulation reference signal, thecertain sequence associated with the generation of the demodulationreference signal received together with the physical uplink sharedchannel scheduled by the downlink control information is [1 1] in a casewhere the temporary Cell-Radio Network Temporary Identity (C-NRTI) wasused to transmit the downlink control information, the certain sequenceassociated with the generation of the demodulation reference signalreceived together with the physical uplink shared channel scheduled bythe downlink control information is selected between [1 1] and [1 −1] onthe basis of cyclic shift information included in the downlink controlinformation in a case where the terminal apparatus uses the orthogonalcover code for the demodulation reference signal and the temporaryC-RNTI was not used to transmit the downlink control information.